DE2224926A1 - FLOW REGULATOR, IN PARTICULAR FOR INFUSING PARENTERAL LIQUIDS, WITH MAGNETIC LOCK VALVE - Google Patents

Description

Patent attorneys Dipl.-Ing. R Weickmawn,

Dipl.-Ing. H. Weickmann, D1PL.-PHYS. Dr. K. Fincke Dipl.-Ing. R A.Weickmann, Dipl.-Chem. B. Huber

8 MUNICH 86, 9 9 9 / QOC

SAHA. POST BOX 860 820 ZZZH CJ Z

MÖHLSTRASSE 22, NUMBER 48 39 21/22

<983921/22>

SCI SYSTEMS, INC., 8620 South Memorial Parkway, Huntsville, Alabama 35802, V.St ₀ Ao

Flow regulator, especially for infusing parenteral fluids, with a magnetic shut-off valve.

The invention relates to flow regulators and magnetic shut-off valves for such regulators. In particular concerns the Invention a device for controlling the flow of parenteral fluids into the veins of a patient.

The usual method of parenteral fluids, such as Administering blood, saline, etc. to hospital patients is very time consuming. Usually the amount of fluid will be per unit of time (flow rate) monitored by a nurse who counts the drops, which emerge from a bottle within a predetermined time and thus measure the flow rate. As soon the nurse notices that the bottle is empty or that something is blocking the flow, so she intervenes and fix the situation. Not only is this process time consuming, but it is something dangerous for the patient in some hospitals because the nurse or other person supervising it usually unable to find the time to continuously monitor the system and ensure that that neither the flow is blocked nor the bottle empties.

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In the past a variety of automatic Flow regulators for parenteral fluids become known. Many of these institutions regulate the flow, by changing the fit of a clamp that clamps a flexible tube that goes into the patient's vein leads. Other regulators knead the tubing to pump the fluid to the patient, but this is not beneficial, because it often leads to permanent deformations in the hose, so that the desire possibly the con * · troll over the flow rate loses "

Other regulators have been proposed in which the Flow rate is controlled by means other than variable clamps. These older controllers, however, require the Formation of inlets in the insertion tube, making it easier for the liquid to contaminate comes. Other devices that do not have this disadvantage often require an extraordinary amount of electrical equipment Power and / or complicated facilities for proper operation, making them unreliable, bulky and make it extremely expensive «

A serious problem with the known regulators is that they either allow the infusion of air into the vein allow the patient or overdose of the fluid given to the patient · Sometimes also occur both cases. Solo devices are therefore quite unsafe "

Another problem with entering parenteral fluids is that blood clots that may form in the needle end up in the patient's yen . This can lead to a serious interruption of the infusion «»

Numerous well-known bodies that have one or more

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possess the mentioned defect and / or in relation to the Subject matter of the invention are in US-PS 2,254,833,

2 576 168, 2 925 8H, 2 962 593, 3 OH 481, 3 105 511,

3 163 176 and 3 348 543 described «

As can be seen from all of this, it is the task of the present Invention to provide a relatively simple, safe, and inexpensive flow regulator using those described above Avoids disadvantages. This includes a fluid control valve that can be operated without the Contamination of feeding access routes into the liquid flow would be required by the valve, but which manages with a minimum of actuating force and a high Degree of security. This also includes designing such a controller in such a way that it operates with a minimum to monitor parenteral fluids automatically administered in a predetermined amount per unit of time, but without the risk of air infusion or overdose · It is also necessary to have a to provide such a system with automatic signaling devices, which alert you when intervention by the supervisor is required · This will make the Increased patient safety. Finally, it is also necessary that such a system be reliable and compact and easy isto

A feature of the inventive solution to this problem is that a flow meter is provided with a special magnetic valve for controlling the liquid flow. The valve has a seat and a movable valve body that can lie against the seat. The valve body has at least one portion which is made of a magnetic material _or by means are provided to create a magnetic force on the valve body to exert that it laterally away from its seat, and in this way the valve will open · In a preferred exporting "

In accordance with the invention, the valve body has an elongated rod which extends in the direction of the flow of liquid · An electromagnet is arranged outside the line which pulls the rod against the side walls of the line in order to tilt the valve body from its seat controlled that the electromagnet is applied repeatedly for different periods of time and that the rate of flow is determined by such periods of time.This system is used to control the flow of parenteral fluids in connection with a drop detector, as well as with control devices that the time sequence of the Activate the valve as a function of the time sequence of the droplet formation. A safety device is preferably provided by which the shut-off valve is automatically closed if a malfunction or a longer deviation from the formal behavior occurs in the operation of the system for ₉ s o that air infusion or overdosing is avoided *

The invention will now be explained in more detail using an exemplary embodiment in conjunction with the drawings

Figoi shows a flow regulator in a perspective view for parenteral fluids constructed in accordance with the present invention;

Fig. 2 shows a schematic top diagram of the shown in Fig. 1, provided system;

3 and 4 show a preferred embodiment of a part of the valve used in the system shown in Figures 1 and 2;

Figo5 and 6 each show an alternative embodiment of a Valve to a system as shown in Figures 1 and 2;

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lig, 7 represents a wave diagram that in qualitative Way the time limitation of various electrical signals of the system shown in FIGS shows;

Fig. 8 shows a schematic diagram, partly in cross section, of a preferred embodiment of the invention;

Fig. 9 is a more detailed subject matter Diagram of part of that shown in Figο8 Systems;

Fig. 10 is a waveform diagram showing various electrical signals in the system included in Figs Fig. 8 and 9 is shown

Fig. 1 shows a parenteral fluid thermoset flow regulator 10 in accordance with the present invention which is being used to control the flow of parenteral fluid from a storage bottle 14 to a patient 12 to überwaoherio The bottle 14 hangs from a vertical post by means of a handle 16 down. From the bottle 14 flows A liquid drop by drop into a drop chamber 20 and then through a flexible hose 22 to a control device 24 which controls the flow through the hose and then through a further sole tube 26 through a needle (not shown) into the yen of the arm 28 of a patient 12. The control unit 24 is attached to the post 18 by means of a bracket 25

Among other things, the formation of droplets 36 when exiting the bottle 14 into the droplet chamber 20 can be determined Pair of electrodes 34 are provided. On the front of the control unit 24, a setting disk 44 is arranged, which serves to adjust the Durohflussrate of the parenteral fluid to a desired value, and the in Hilli-

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liter or in drops per hour or in another Ubliohen Unit is calibrated. The control unit exercises a ver ~ gleiohsfunktion from such that when the rate of drop formation and, accordingly, the flow rate by one a certain amount is greater than the rate set on the setting dial 44, a lamp 40 lights up to indicate this Report to a nurse or other person supervising the process · In the same way another lamp 38 lights up when the flow rate is less than that set by a certain amount Guess to also indicate this. ”Another lamp 79 lights up every time a drop of liquid falls into the drop chamber 20. The signals from the drop detector electrodes 34 and a sensor 30 for the liquid level are connected to the control unit 24 by a small cable 46 forwarded

The sensor 30 for the liquid level extends near the top into the one hanging with its top down Flasohe 14 · When the liquid level in the bottle falls below the top of the probe 30, one will light up Lamp 32 on controller 24 comes on to inform the nurse that the fluid level is too low and that the bottle has to be changed or that the patient has received enough fluids

In addition to lamps 38, 40 and 42, if desired, other warning devices can also be provided central station, where the operation of many such systems can be monitored in the usual way.

Fig. 2 shows a similar diagram of a Duron flow regulator for parenteral fluids as shown in Pig »1 is · The details of running a solohen

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Heglers are now explained with reference to Fig. 1 and 2.

Magnetic »shut-off valve

As shown in Fig. 2, the flow of parenteral fluids through the tubes 22 and 26 into the patient's vein is controlled by means of a magnetic shut-off valve 50. The valve comprises a normally vertical valve housing 52 _f made of non-magnetic material such as plastic (acrylic resin, etc.) The ends of the tubes 22 and 26 are inserted into the end openings of the housing 52. A circular flange 54, which forms a valve seat, and a movable valve body 56 are arranged within the housing Cross-section and is provided with a rod 58 which extends upwardly into the housing, parallel to the direction of flow. The valve body 56 also has a lower, laterally extending base 60 which normally rests on the valve seat 54 and closes the valve. The pressure created by the liquid in the hose 22 and the top of the housing 52 force the valve body against its seat, so that a check valve is formed Press seat

An electromagnet 70 is arranged near one side of the housing 52. The solenoid 70 has two pole pieces 71 and 72 in the housing and by the same hinduroh generate a magnetic field _o The main lines of force of the magnetic field generated by the electromagnet 70 are indicated by dashed lines ·

The upstanding rod 58 of the valve body 56 is

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made of magnetic material such as iron or the like and old coated with an inert plastic material, to prevent chemical reactions between the metal and the parenteral fluid. When the electromagnet 70 is applied, the magnetic field generated thereby pulls on the magnetic rod 58 and tilts the valve body 56 to the left until the rod 58 contacts the side walls of the housing 52 · This opens the valve and the flow of the liquid is released. When the electromagnet 70 is then switched off again, the pressure changes the liquid in the hose 22 and in the upper part of the housing 52 return the valve body to its upright position, which closes the valve again

Figures 3 and 4 show a preferred embodiment of the valve housing 52 and the valve body 56 "Fig. 3 shows the valve body 56" as it rests on the valve seat and the 4 shows the valve body in its tilted position, in which it has an opening 94 for the flow of Durohm through the valve releases

The housing has an indentation 84t around its circumference acts as a stop to prevent the sole from entering too deeply into the valve housing

The valve body 56 is preferably made of a solid one Plastic body 90 made of a lightweight plastic material such as acrylic resin o It has the shape of a truncated cone and is provided with an elongated iron or steel rod 88 extending longitudinally extends into the center of the body 90 · At the bottom of the valve body 56 is a white rubber washer 92, which is a resilient, liquid-sealed seal forms when pressed against the round edge 93 of the valve seat

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The shape of the valve body is highly advantageous because it utilizes the forces that occur as a result of the flow of liquid in the direction indicated by arrow 95 to assist in opening and closing the valve the scope of the control unit 24 can be reduced to a minimum · Once the solenoid moves the valve body 56 a little out of position tilts away on the valve seat, the flow of the liquid through the opening 94 generates forces on the inclined surface of the body 90 and in this way creates a lateral force component which acts on the valve body 56 against the side wall of the housing 52 and, together with the magnetic force, to keep the valve open The force generated by the flowing liquid, however, is not enough to keep the valve open by itself; the Magnetic force is therefore required

When the magnetic force ceases, it is due to the downward pressure of the liquid on the valve body on the Body 90 attacking force strives to swivel the valve body into its original vertical position zurUokzusohwenken and so to close the valve quickly and tightly. The pressure of the liquid then keeps the valve closed until the solenoid is switched on again.

The valve body 56 can be cut as easily as possible. It has been found that the pressure of the parenteral fluid in the line 22 and in the housing 52 is sufficient to press the valve body 56 onto its seat, even if the valve is pivoted completely from top to bottom when the valve body is not too sohwer. Using a solid Akrylharzkörpers 90 and an iron bar 88 is formed "in valve body leioht enough to act in this way ₀ The rod 88 is preferably made of an inexpensive material,

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such as soft iron, which has a relatively high permeability and a relatively low coercive force · Bs is favorable if the rod has been permanently magnetized by the electromagnet 70

An alternative embodiment of the valve is shown in FIG. In this embodiment, the flat tube 54 of the housing 52 which forms the valve seat is arranged in a higher position than in the embodiment as shown in FIG and 4 is shown. Furthermore, a further indentation 96 is provided here at the lower end of the housing, in which the end of the hose 26 is seated

The valve body 97 has an I-shaped cross section, as does the valve body 56, which is shown in FIGS It also has a plastic coating 100 over a rod 98 of magnetic material. An elastic protective cover 102 forms the seat on the upper part of the valve body 97

In the embodiment of Figure 5, the rod extends 98 downstream with respect to the direction of flight through the valve instead of upstream, as in the case of the one in FIGS 2-4 is the case. However, their mode of operation is essentially the same as that of the previous one described embodiment, apart from the fact that the forces of the river do not tend to open the To support the valve, as is the case with the design according to Figo2-4.

Another embodiment of the valve is shown in FIG. In this embodiment, the valve body consists of a plastic-coated ball 104 made of magnetic material Material · The ball is in its remote from the valve seat

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Position shown · When the electromagnet 70 is not energized, the ball rests on the valve seat 54 and blocks the flow of liquid. However, when the electromagnet is applied, the ball pivots on the edge 93 of the valve seat 54 such that it is pulled up against the left side wall of the housing 52 away from the seat The location of the pivot point 93 is to the left of the center of the sphere, so that this again hit the seat as soon as the magnetic field disappears.

A Sohweimmer 105 is also provided in the chamber 52. The buoyancy of the float 105 is so dimensioned that when the valve is rotated 180 °, the flow presses the ball 104 against its seat 54 and keeps the valve closed, although it does upside down is ₀

In either embodiment of the magnetic valve, the movable valve body 56, 97 or 104 is pulled aside to remove it from its seat. The side wall of the Valve housing serves as a stop that prevents the valve body from moving beyond a point where he would continue to rest on the stop and hold the valve in an open position. In other words, the The stop keeps the valve body in a position of unstable equilibrium, so that it is always pulled back to its seat is when the magnetic flux disappears, whereby the correct functioning as a check valve is ensured. The stop holds each valve body in a single position that the liquid flowing through the valve touches the valve body presses on his seat. This is important for patient safety when the valve is in a system is used to administer a parenteral fluid. Because this ensures that the to the vein the patient's hose is closed as soon as the electrical power to the regulator fails or when

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the regulator is disconnected from the valve due to a mishap ο In addition, this prevents a dangerously high amount of liquid per unit of time from getting into the patient's yen.

It is understood that the term "magnetic Material "here not just bisen or other ferromagnetic materials Material is to be understood, but also permanent magnetic materialIn another embodiment of the invention, ZoB. if the rod 58 of the valve is a permanent magnet, the valve can only be opened by that one brings a piece of soft iron against the outside of the housing 52, so that the magnetic attraction between the iron and the permanent magnet causes the valve body 56 to tilt. As explained above, however, is preferred the source of the magnetic field is external to the flow line, and the rod 88 is not permanent magnetized

In a further embodiment of the invention, which is also shown in FIG. 2, the valve can be open for a long time be held, for example to clean the system or for similar reasons, namely by using a permanent magnet 51 against the outside of the valve housing 52 o This permanent magnet then holds the valve rod 58 against the side of the housing so that the valve is held open as long as desired

Control circuit

The control circuit of the flow regulator 10 is shown in Pig * 2. The adjusting disk 44 of the control device 24 shown in FIG. 1 regulates the frequency of the pulses of a conventional one Clock 62o The clock pulses are a timer 64 fed to it to an oscillator control circuit

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66 passes on »The oscillator control circuit 66 switches a conventional oscillator 68 off and on. The oscillator operates the electromagnet 70 ₀

A frequency selector 72, which by means of a button 42 on the Front panel of the control unit 24 can be operated, it allows the frequency of the oscillator to at least two to set different values The frequency selector 72 is basically a switch which is used to select one of two to switch on various resistors in the usual resonant circuit of the oscillator 68

The upper part of FIG. 2 shows the screw cap 48, which is fastened to the bottle 14, in a similar manner. The screw cap is made of insulation material and has at least one opening 80 through which parenteral fluid flows and thereby forming drops 36. The screw cap 58 also has one Air opening which is not shown and which allows air to penetrate into the bottle in the form of a liquid emerges from this

The drop detector electrodes 34 are spaced apart from one another such that each drop 36 has both electrodes. the 34 touched in its formation * Most parenteral fluids have a high electrical conductivity · Auf in this way each drop forms a conductor between the electrodes 34 and closes a circuit between a positive voltage source V and a drop detector 76, which generates an output every time a drop is detected. The voltage V of the voltage source is kept relatively low, preferably below 1.2 V, to avoid electrolysis of the liquid takes place o

Each pulse generated by the drop detector 76

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is sent to the oscillator control circuit 66, as well as to the timer 64. The oscillator control circuit 66 acts in such a way that it einsehaltet the oscillator 68 and sets in motion ₉ when it receives a clock pulse "on and off it when a drop pulse from the drop detector 76 receives. In this way, the period of time that the oscillator is on is a puncture of the drop formation rate. This function is such that the drop formation rate is kept equal to the rate of the clock pulse generation by the clock pulse generator 62.Since the pulse rate of the clock pulse generator 62 can be kept at an extremely precise value, it is also possible to control the drop formation rate and accordingly the duration rate Comply with the patient's veins with a relatively high degree of accuracy

Pig.7 qualitatively shows the time relationship between clock pulses 106, drop pulses 114, 116 and 118 and the bursts 108, 110 and 112 of the output pulses of the oscillator 68. The timing of these pulses is illustrated relative to the time of the drop formation.

The leading edge of the first pulse 106 turns on the oscillator 68.In this embodiment of the invention, the frequency of the oscillator 48 is preferably a multiple of the frequency of the drop formation.The oscillator continues to generate pulses until a drop is formed and a drop pulse 114 which turns off the oscillator During this time, the oscillations of the oscillator have repeatedly turned the electromagnet 70 on and off to repeatedly lift the valve body 56 from its seat and push it back onto it, allowing any single reciprocating motion allow a subset of the liquid to pass through the valve _{o the} frequency and amplitude of the output of the oscillator 68

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preferably set for each period of the operation. In this way, the amount of fluid that flows through the valve depends on the number of cycles in one Impulse burst of the output oscillations of the oscillator 68 during one period of the operation from «.

The control circuit works according to a feedback method as follows: The rate of drop formation depends on various factors. One factor is the level of fluids in the bottle 14 'another factor is the pressure. the The drop chamber is airtight and the pressure in the chamber can counteract or assist the formation of the droplets at the outlet of the opening 80. If the chamber 20 is relatively When it is full, the air in it is compressed and creates a back pressure that controls the rate of droplet formation On the other hand, if the liquid level in the chamber 20 is low, then the air pressure is also relative low and drops are formed accordingly faster.

The counterpressure in the drop chamber 20 can vary according to a change in the counterpressure from the veins of the patient change, line increase in this back pressure can take place, if the patient ζ · Β. coughs or turns over or when a child patient screams.

If, in any case, the drop formation rate decreases, as shown in the thematic representation of Fig. 7 by the small set a longer time interval between the first and second drops compared to the second and third drops. is schaulioht, then a longer pulse pulse 110 of Vibrations from the oscillator are delivered to the electromagnet, which results in a greater number of liquid subsets flows through valve 50. This reduces the pressure in the drop chamber 20 and the following

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Drops form faster · This causes the next series 112 of oscillations from the oscillator 68 is shorter than the previous · Series 110 · Possibly the balance between the drop formation rate and the length of the SohwingungSeries reached »so that the drop formation rate is synchronized with the time pulse rate

As shown in FIG. 2, both the clock signals and the drop detector signals are fed to a comparator 78. The comparator 78 includes counters for counting the drop signals and the clock signals, as well as means for comparing the counting results of these two counters. If the rate of droplet formation is more than about 10 # below the clock rate, an output signal is provided to lamp 38 to illuminate it, indicating that the droplet formation rate is too low. If the drop rate is more than about 10 # higher than the clock rate, a signal is provided to lamp 40 to indicate that the drop rate is too high. A nurse or other supervisor can then see that either lamp 38 or 40 is lit and is thus able to put things right again. A 20 # dead band x ^{1 of} the same 78 is provided to prevent the lamps from lighting up when only one or two drops are exposed, such as when the patient coughs, moves or when the drop formation rate only temporarily increases was high.

The signals from the drop detector, both the timer 64 and the oscillator control circuit · supplied 66 the drop pulses activate the timer so that it will ever switched "membranously when a pulse arrives ₀ When a predetermined period of time, no pulses arrive, the timer outputs a switch-off signal to the oscillator circuit 66 and to the oscillator 68 to make the oscillator fully

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come off and close the valve 50, in this way to prevent fluid from flowing into the patient's blood. This indicates a difficulty that a supervisor can remedy. The timer 64 also causes the valve to automatically close and prevent air from entering the patient's yetien when the liquid in the bottle 14 is completely emptied or when there is a blockage in the flow of liquid from the bottle. The period of time during which the timer 64 is activated corresponds approximately to the period of time which the drop chamber 20 requires for it to be completely emptied

As already mentioned above, the valve 50 provides security in the event that the electrical supply for the Hegler fails. Because in this case the valve closes automatically by the normal mechanical forces occurring on it, so that an excessive increase in fluid or air cannot reach the 7% η9Ά of the patient «

The frequency selector 72 is provided in order to adjust the frequency of the oscillator to the size of the drops formed. Hanohe types of screw cap 48 have.iwei Drop outlets 80 instead of a single one, the The size of the outflow openings is different. The nurse or the doctor can choose which outflow opening should be used in each case.

The frequency selector causes a decrease in the frequency of the oscillator at large drops and an increase in Fre · * »queni when small droplets are formed ₀ Because the Duron" fIuSratβ through the valve 50 is a direct function of Ossillatorfrequenz, causes an increase in the frequency AUOH

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an increase in the flow rate through the valve and vice versa. In this way the frequency selector causes the setting of the adjusting disk 44 can remain the same despite a change in the size of the droplets

The electrode of the liquid level sensor 30 comprises an insulating drill hole and an electrode wire 82, which extends upward from the bore. The wire 82 is connected to a supply circuit 74 for the lamp 32. When the conductive liquid is in contact with the tip of the wire 82, a circle is closed and the The lamp is switched off. However, if the liquid sinks below the tip 82, there is no conductive connection between the liquid and the wire 82 and the circle 74 so the lamp 32 stops.

The use of the magnetic shut-off valve 50 is highly beneficial · The amount of electrical energy that which is needed to open the valve is relatively small. Accordingly, the control unit and electromagnet can be of relatively compact construction. Also depends the valve 50 does not prevent the flexible hoses 22 or 26 from being squeezed or pinched. so that this can remain closed to prevent contamination.

Another advantage of the invention is that the flow through the check valve is in partial amounts rather than in one constant way is equal to the outflow from the bottle 14, which is also in partial quantities, namely in individual drops, · It is obvious that the size of both of these subsets depends roughly in the same way on the viscosity depends on the liquid In this way, a change in the flow rate through the valve and in the drop formation rate due to a change in viscosity are canceled out.

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mutually dependent on each other · Furthermore, it is to be understood that the Fluctuation of the valve body · of the yentile helps to keep the valve free from clogging «Although the Use of the oscillator is not absolutely necessary, but it allows the size of the drops to be increased without changing the flow rate setting on the adjusting disk 44 »

Preferred embodiment

The Mgo8-10 show a preferred embodiment of the parenteral fluid flow regulator according to the present invention. Many details of this execution are the same as in the training example already described. Accordingly, be for same The same reference numbers are used for components

Input member

While the flow regulator described so far uses a screw cap 48 for the storage bottle 14, the The embodiment of FIG. 8 has a bottle 14 which is closed with a rubber lid 124. There is an opener for this purpose 122 provided. The opener 122 has a pointed one End 126, which is pierced through the rubber cap 124 into the bottle in order to create a hole in the rubber cap in this way and to form a secure seal around the opener

The pointed end 126 of the opener 122 has three channels · Duroh a channel 128 can air in via an air hose 138 The container can penetrate through a channel 130 which runs through the opener and an outlet opening with a surrounding one has annular lip 131, liquid flows out of the bottle. The lip 131 serves as a surface for the drop formation. A third channel (not shown) is filled by the sensor 30 for the liquid level, whose electrode consists of a conductive rod or wire, the tip 82 of which extends upward from a

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insulating cover extended

From the non-conductive plastic body of the opener 122 three electrical connections 132, 134, 136 extend laterally outward. The top connection 132 is through the insulating material of the opener 122 is connected to the wire 82 of the liquid level sensor 30 · Inside of the opener 122 there is no connection whatsoever between this connection and the liquid

The second terminal 134 has a conductive tip 137 which extends into the liquid channel 130 and thus makes contact with the liquid emerging from the bottle manufactured

The third terminal 136 passes through the insulation of the opener 122, extends downward through the base of opener 122 and has a tip 140 positioned just below the outlet of liquid channel 130 isto

The drop chamber 20, the hoses 22 and 26, the valve and the electromagnet 70 are identical to the corresponding elements in the embodiment of Figo1 «7ο

The conductive tip 137 of the terminal 134 in the opener 122 makes electrical contact with the liquid in both bottle 14 and liquid channel 130. In this way, the connection 134 serves as an electrode for the detector circuit to indicate that the liquid level is too low Port 134 also serves as a port for the drop detector of this invention

Drop detector

The drop detector shown in FIG _o 8 has a detector electrode tip 140 with such a waste

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stood below the underside of the lip 131 that a drop 144 (shown in dashed lines), which is being molded is not large enough to make contact with the tip 140 · On the other hand, however however, the tip 140 is close enough to the lip 131 that the drop, after it has assumed the shape indicated in the solid lines 142 in length and width before completely detaching itself from the lip, touching the lower part of tip 140 and creating a momentary fluid path between tip 140 and electrode 137. Since the parenteral fluid (a saline or sugar solution or the like), usually of proportionately If the conductivity is high, a low-resistance path is created briefly between the electrodes 140 and 137 in this way This allows the current to flow from a power source through the liquid and electrodes 137 and 140 flow and in this way generate an electrical signal, which indicates that a drop has fallen

One advantage of this drop detector is that Droplets which splash upwards when a drop falls into the liquid in the drop chamber 20, mostly not are large enough and in the correct position to allow contact between the liquid emerging from the channel 130 flows, and the electrode 40 to produce «In this way, there are hardly any false displays of drops as a result of a Spritζens ·

Another advantage of this detector is that the period of time in which the conductive connection is established between electrodes 140 and 137 is relatively uniform iff · For example, for the parenteral fluids mentioned above, the drop detection time is about 50 ms and is relatively constant »

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Another advantage of the described drop detector is that it is very difficult, if not impossible, for a partially formed drop to get into one To come to a situation in which he does not make contact with the electrode 140 but does not fall. This is because the Drop is only detected when the process of its separation from the upper liquid has begun, and this is practically irreversible. It is thus evident that the detector is unable to continue the formation of Can mistakenly display drops

Durohm flow regulator

Pigo8 also shows a block diagram of the flow control circuit of the present preferred embodiment of the invention. The regulator circuit includes a "drop sense amplifier" 146, which amplifies the drop detector signals and signals corresponding to an integrator 150 provides · The output of the integrator is passed to an ^M-valve control circuit ^H 166 whose output drives the coil of the electromagnet 70, with direct current pulses whose Duration and repetition rate varies, their. Strength is constant, however. The integrator 150, the operation of which is controlled by a "rate control loop" 152, in turn controls the time rate of opening and closing of the valve so that it opens and closes once each time a drop is detected.

The "liquid level sensor amplifier" 148 amplifies the signal that is generated when the liquid level is too low, and activates a "low level alarm ¹¹ -reia 158, which lights up the lamp 32 (see FIGS. 1 and 2), to indicate that the liquid level in the bottle 14 is too low

Finally, there is also a "SohwaohfluÄ detector circuit" 154 and a · 'high flow detector circuit "156 provided · each

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which activates a corresponding alarm circuit 160 or 162 to activate a lamp 38 or 40, which indicate that the flow rate is a predetermined amount below or above a desired value. Of the The value for the desired continuous flow rate is set by the setting dial 44 which controls the rate control circuit 152 hires »

Each of the alarm circuits 158, 160 or 162 actuates a remote alarm circuit 164 which sends a signal to a nurse station or the like to draw attention to the fact that action is required

In addition, a blocking protection circuit 155 is provided, which automatically ensures that a certain minimum of liquid flow is maintained so that the Always flush the patient's veins to avoid clumping in the infusion needle

Flow regulator in detail (Fig, 9)

Fig.9 shows in detail a circle with which in more useful Way, the functions described with reference to Figο8 carried out can be »The shim 44 (Figoi) is with connected to the wiper arm of a potentiometer 198, the one Part of the rate control circle 152 was The Adjustment Screen 44 also operates a main switch 252 which turned the device on and off. The potentiometer has an outermost one Compare left setting labeled "OCW" and an extreme right setting labeled "OW" Fig.9o The switch 252 is open when the adjustment knob of the potentiometer is in the "OCW" position. A turning The clockwise direction of the button closes switch 252 and connects a power source 165 to the control circuit

The power source includes a rechargeable 6.25V battery 250 one, which is in series with a rectifier diode 248 » a resistor 246 and the secondary winding of a trans-

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formator 254 is connected · The primary winding of the transformer 244 is connected to a plug 242, which is plugged into a standard three-wire household set socket for 60 Has and 110 V can be plugged in. The battery 250 is known Type of the type used as a Weohselstrom filter to convert the rectified Weohselstrom half-waves to the To smooth battery soles. When the switch 252 is closed, a voltage of approximately 6 V «is between the Terminals 134 and 170. Terminal 170 is held at ground potential and terminal 134 is thus at -6V. Port 134 provides a common port for many of the control circuits and line 170 provides one positive bias with respect to line 134o

It will be understood that it is beneficial if any source of alternating current from the usual power supply network or another power source can be used instead of the Battery 250 if possible. In addition to acting as an AC filter, the battery is primarily intended for hot cases or for portable devices when no conventional power source is available «,

The three detector terminals are connected to the opener 122 connected by means of a socket 135 of the drop detector terminal is connected to a Vorspannungswiderstandschaltung consisting of the resistors 172 and 174 _o The upper terminal of this combination is connected to the line 170th If, therefore, the electrodes 140 and 137 are briefly connected by the liquid when a drop falls, a 6V signal is generated across the resistor combination 172-174 Amplifier transistor 188 "

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Integrator circuit

Ak output of amplifier circuit 146 is a capacitor 190 connected to a terminal (+ terminal) to the collector of transistor 188. During the period in which the Transistor 188 is switched off, the + terminal of capacitor 190 is at 0 Vo} t, which represents a positive voltage in relation to its right (negative) terminal. The charging current flows through a light emitting diode ("LED") 186 and a resistor 184 connected to the power source line o When transistor 188 is turned on by receiving a drop detector pulse the charge stored in the capacitor 190 is suddenly fed to the integrator circuit 150

The light emitting diode (LSD) 186 is arranged on the front panel of the control device 24, as shown in FIG. It is designated there by reference number 79 · You preferably emits green Lioht for a short period during which each receive a drop detector pulse "In this way, the proper I ¹ IuB in the ELttssigkeitezuführungeeystem be visually überwaoht by a nurse or a doctor, or from another person to be monitored or even from the patient himself, only by observing the green strand of wire, which indicates that drops are falling

Using a light emitting diode instead of one Lamp in the example of Fig.1-7 is advantageous because such diodes have a much longer life than most lamps

The integrator circuit 150 includes a capacitor 192 and a series resistor 206 which is equal to the resistance of the Potentiometers 198 are held one behind the other. The sole arm 200 of the potentiometer 198 is via a transistor

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293 in the amplifier 148 for the liquid level indicator connected to the feed line 170 · The transistor 293 is normally on and is only switched off when the liquid level in the reservoir drops below the tip 82 of the sensor 30 for the liquid level o The grinding arm 200 is therefore normally with connected to a voltage source which is positive with respect to the voltage at the lower terminal of the integrator capacitor 192 is «,

The resistor 206 and the potentiometer 198 continuously draw charge from the capacitor and in the process strive to maintain the voltage e "at the upper (positive) terminal of the capacitor 192 · Sine diode 194 is located «know the positive terminal of the capacitor 192 and the negative terminal of the capacitor 190« At the junction between the diode 194 and the negative terminal of the capacitor 190 there is a clamp diode 196 ·

When transistor 188 is off, the positive terminal of capacitor 190 is at bull volts while the negative terminal is at approximately -5.2 volts. If the fran » sistor 188 is on, between the positive terminal of capacitor 190 and the negative 6 V terminal 134 is on connected low-resistance path. In this way • the voltage at the positive terminal suddenly changes from 0 to -6 volts. The negative terminal of the capacitor 190 tends to take higher negative values to compensate for this sudden change · compartment drop of the negative However, the diode 194 and the charge stored in the capacitor 190 become conductive by about 0.4 volts is transferred to capacitor 192. This sudden Transfer of the charge to the capacitor 192 causes an associated drop in the voltage e «. The capacitor 192, however, has a capacitance which is about 15 times higher is than that of the capacitor 190 · For example owns

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the capacitor 192 47 yui and the capacitor 190 3 »3 / u $ · In this way, the voltage e ₂ drops only about 0.4 volts.

As already mentioned above, the length of a drop detector is pulse usually only 50 ms. When it ends, transistors 176, 178 and 188 are turned off and the positive terminal of capacitor 190 suddenly returns to 0 volts then strives to increase a corresponding voltage value. Meanwhile, the diode 194 quickly becomes opaque, while diode 196 becomes conductive and, in conjunction with resistor 212, the negative terminal of the capacitor 190 again applies to about -5.2 volts. Capacitor 190 is then rapidly passed through IiED 186 and resistor 184 charged to make the capacitor ready for the next drop detector pulse

As already mentioned, charge is continuously withdrawn from the capacitor 192, specifically in an amount per unit of time which is determined by the setting of the potentiometer 198 by means of the adjusting disk 44. Immediately nadb. the sudden drop in voltage e ₂ , it rises again essentially linearly until the next drop pulse arrives. This results in the sawtooth-shaped curve shown in FIG. 10 shows the drop detector pulses e ^ in their temporal relationship to the course of the integrator output voltage e "and the output voltage e _Q , which is fed to the electromagnet 70 to close the valve to open. It can be seen that the amount of charge delivered by capacitor 190 to capacitor 192 is always the same, so that the drop in voltage e «remains the same for each drop

Valve control circuit The integrator output β £ is connected to the valve control input.

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circuit 166. More precisely, voltage ₂ is applied to the base of transistor 208, which is connected to resistors 210 and 212 to form a limit value detector circuit. The limit value up to which the voltage e ₂ must rise in order to be able to switch on the transistor 208 is represented by the dashed line ^H A ⁿ in Pig.10.

When transistor 208 turns on, it turns on two more transistors 222 and 228 between the collector of transistor 222 and the collector Another transistor 216, which is normally off, is a resistor 218. The lower end of the resistor 218 is connected to the base of another transistor 232 and connected to a bias resistor 234, the other end of which is connected to the -6 volt line 134. Before transistor 222 is turned on, its collector voltage is about -6 volts. However, when transistor 222 is closed, its collector voltage rises to near zero, with a bias signal to resistor 234 is given by turning on transistor 232.

The collector terminal of transistor 232 is connected to the negative terminal 236 of the coil of the electromagnet. When transistor 232 is on, the voltage on terminal 236 changes from zero to -6 volts. The positive terminal 238 of the coil of the electromagnet is connected to the neutral conductor 170 via the transistor 228. Thus, when transistor 232 is on, the system supplies direct current to the coil of electromagnet 70.

When the system is operating normally, fluid will flow through the now open valve for 100 to 250 milliseconds, one more drop is noted ο If this one

2 0 9 Q 8 2 / (J Π η Ο

If further drops are detected, the Traneistor 176 switched on again. The collector of transistor 176 is connected to the base of the transistor through a resistor 180 216 connected. In this way transistor 216 becomes a * switched. This will bias the transistor 232 of -6 volts short-circuited, turning off transistor 232 and terminating power to the Electromagnet 70 causes the y-valve to close

Fig. 10 shows the output pulses of the e ^ voltage generated by the system described above can be generated during its normal operating sequence. It should be noted that the The height of the eQ-impulses is constant · The length of the impulses, however, as well as the time interval between the impulses varies in relation to the changing conditions of the system

As noted, the time between individual drop formations changes in relation to a number of different parameters. The control circuit, however, compensates for changes in the droplet formation rate by causing an increase or decrease in the constant flow rate through the valve so that the mean flow rate through the valve corresponds to the desired flow rate as determined by setting dial 4-4. If Z ₀ B. (cf. Pig »10) the first two drop impulses e ^ are too far apart, which indicates a continuous flow rate below the desired value, then the voltage » 2 rises for a longer time than normal and thus to a higher one Voltage value than it was reached in the previous processes and the output pulse (a) extends over a longer period of time. However, this also means that more fluid flows through the valve. Since the system is a closed circle servo system, the larger one has the effect

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Durohfluss a faster formation of the next drop However, since the voltage e « has risen to a higher value, the voltage »- limit value" A% of the start of the next output pulse (·) Is required to be reached earlier than Torher. Through this the pulse (b) becomes shorter and the flow through the valve is reduced. Same variations will be in the determination the duration of the next output pulse (d) and further pulses are effective. The flow rate is based on this Way directly proportional to the drop formation rate

Rate control area

The rate control circuit 152 includes a potentiometer 198 and a resistor 206 and resistors 202 and 204, from de * each is connected to the potentiometer winding at a selected point. The opposite connections the resistors 202 and 204 are connected to one another and the diodes 194 and 196 are connected to a common point connected «This arrangement is chosen to give the potentiometer 198 an approximately logarithmic characteristic of its Enter the setting, with a range of about seven octaves, so that the dial 44 can be read in milliliters per hour.

With a predetermined setting of the potentiometer 198 for regulating the flow rate to a specific set rate, the tendency for the increase in the voltage eg is am Output of the integrator constant · The slope changes however with every change in the setting of the potentiometer 198, with the result that the temporal separation between the output pulses e «also decreases or increases in accordance with the increase or decrease in the desired flow rate set."

Safety Considerations An advantage of the present invention with respect to the

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Safety is that the solenoid coil 70 is never energized for more than 250 milliseconds. This ensures that each individual received Drop signal the valve is opened and closed again. In this way it is prevented that as a result of a Malfunction of the electronic device or a blockage in the flow of fluid to the patient, which causes a substantial delay in the formation of the next drop causes the valve to be held in its open position

This automatic shutdown is brought about by the combination of a resistor 226, which is connected to the negative terminal 236 of the solenoid coil and to the collector of the transistor 232, with a capacitor 220 and a transistor 224. The capacitor 220 and the resistor 226 together form a timing circuit When transistor 222 is turned on, the voltage on the negative terminal of capacitor 220 and the collector of transistor 222 increases from -6 volts to slightly less than zero volts. Before transistor 222 is turned on, the positive terminal of capacitor 220 is Connected to zero volts through resistor 226, solenoid 70 and a relatively large resistor 240.However, when transistor 222 is turned on, then the positive terminal of capacitor 220 rises to approximately +5.4 volts and transistor 232 is turned on, which results in a connection of the lower terminal of resistor 226 to -6 volts The capacitor 220 then begins to discharge through the resistor 226 »

If transistor 232 is turned off upon receipt of the next drop pulse before the voltage on capacitor 220 has a sufficient value to generate the '.'..-. Ui; i ator switch 224, the circuit operates in "* * ■> turnips described normal fashion ₀ However, if within *

i 0 9 8 8 2/0 f, 0 0

If no further drop signal arrives halfway through 250 milliseconds, then the voltage on capacitor 220 decreases to a value by which the switching on of the transistor 224 is effected

The current path generated by transistor 224 short-circuits the base-emitter path of transistor 228 and turns this transistor off. The current from line 170 to the solenoid coil must then flow through the relatively high resistor 240. This instantly drives the positive terminal 228 of coil 70 to "6.6 volts, eliminating the e _Q output and closing the valve. The voltage changes from -6.6 volts to about -6 volts after being in the magnetic field The energy stored in the coil is dissipated. However, the coil remains switched off and the valve remains closed until the setting circuit to be described adjusts the integrator again and enables it to work in the normal way again, and another drop pulse is received.

Resistor 214 is between negative terminal 236 the solenoid coil and the emitter of transistor 208. It effects positive coupling from transistor 232 to the transistor 208 and thus favors the switching on of the transistor 232 and the switching on of the electromagnetic coil »

Every time the safety circuit, as described above, goes into action, a negative going deviation of the collector voltage of the transistor 228 takes place, the does not occur during normal operation. This negative deviation is used to indicate the absence of a drop to feed the indicating signal to an appropriate detector and to the compensation circuit described below

As already emphasized above, the adjusting washer is 44

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(see Figo1) calibrated in milliliters per hour · Since the The rate of flow through the valve is directly proportional to the rate of the transferred electrical charge or from the electrical current flowing away from the integrator, and there also the electrical current flowing out of the integrator Current is a quasi-logarithmic function of the setting of the potentiometer 198, the calibration of the setting is disk 44 approximately logarithmic, so that all points on the scale can be adjusted with almost the same accuracy. In the case of the device that has actually been tested an adjustment of the adjusting disk 44 over its full range a change in the current flowing out of the integrator flows over about 7 octaves "

Since the capacitor 90 is fed from the same current source that is used to control the rate of discharge of the capacitor 192, that from the integrator changes flowing current with the supply voltage in the same proportion as the amount of charge drawn from the capacitor 190. In this way the control of the thermoset flow rate is possible Relatively independent of the supply voltage over the normal operating range.

Low liquid level detector

The detector circuit 148 for indicating that the liquid level is too low comprises a (transistor 293 and preload voltage resistors 295 and 297. The lower terminal of the resistor 295 is connected to the -6 volt line 134 via a connection 132. The conductive liquid in the bottle is in contact with the exposed tip 82 (see Fig. 8) of the sensor 30. This position holds the transistor 293 in place enabled state and allows the rate control circuit 152 to be actuated in the manner described above.

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When the liquid level in the bottle drops below the tip 82 of the probe 30, the circuit is between the conductors 132 and 134 are interrupted with the result that the transistor 293 switches off corresponds to a liquid flow of about 4 milliliters per hour, which is the lowest value available in the device. This low flow rate continues until the bottle is empty, with special care being taken to prevent the flow of liquid at this point Turn off completely to prevent air infusion into the patient's veins · The tent while which the liquid flows with the low durohydrate flow rate, Is sufficient to give a guardian the opportunity to replenish the liquid without turning off the supply completely. "Turning off the transistor 293 Activates the alarm circuit 158 for low liquid level, which turns on the lamp 32 (in this case an LED) as a signal for the person being monitored to replenish the liquid supply.

Detector for excessive flow rates

The overflow rate detector 156 is used to actuate the overflow alarm circuit 162 only when the droplet formation rate has decreased by a minimum higher than a set value which exceed the desired value by less than 3 or 4 drops. The reason for this is that in normal operation every now and then a few extra drops are formed, as well as occasional drops for various reasons fail. In any case, one should only alert the person under surveillance if their intervention is absolutely necessary at that time

The high flow detector includes a port

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sistor 254, the emitter line of which is connected to the output terminal e _{2 of} the integrator circuit 150 via a diode 262 · Between the -6 volt line 134 and the base of the transistor 254, a capacitor 256 and a resistor 258 are connected in parallel Connected to transistor 254 is a resistor 260 which is on the other hand connected to the collector of transistor 178 in amplifier 146 of the drop sensor *

An excessive increase in the flow rate can be caused by a number of deviations. softening can consist, for example, in continuous leakage of the valve. Another possible irregularity can consist in that the valve in its open division is clamped and thereby a continuously borrowed minimal current flows through the system »

The overshoot signals generated by a few extra drops are accumulated in the capacitor 192 of the integrator. The value of the voltage e _g decreases with the extra drops. When e _g falls to -6.8 volts, which corresponds to an excess of three drops above the desired Eatβ, the base-emitter connection of transistor 254 becomes conductive through diode 262, so that transistor 254 turns on to the high flow alarm circuit 162 which then turns on a red EED 40 to notify the guard that attention is required ©

If the deviation is a continuous flow instead of the formation of redundant drops takes place, the amplifier 146 for the drop detector is continuously turned on. In this way through resistor 260 a voltage across the resistor

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258 and the capacitor 256, which is the base with dtr dta transistor 254 are round-shaped · Der Wider · tan * 258 and the capacitor 256 form to amaan tin integrating ·· filters for staircases. Lasts under normal circumstances • wipe in a drop in column he "oh» tea · 50 milliseconds and « successive drops lie ainleeten · 500 Milliee Kund en (500 Milllaakamdan in 4-way design for one maximum Durohfluirate Tea about 35 milliliters per hour ·) · Father nereal Ua tandem charges the capacitor 256 during the curia fropfanlMpulse not enough on »ua den Transistor 254 aiaiuaahaltan · When is Durohflui on the other hand If it takes place continuously instead of dropwise, then will the capacitor 256 is charged to a sufficient voltage, including the Baaia de franüatori 254 roreuepannen and ϋ ··· η Traneietor adhere to this tfeiae den AlarMkrei · 162 for "u hahan Surohflufi in operation au aetaen" • e da0 a · monitoring unprofessional can intervene ·

JeKctor for low flow and alarm systems

It has already been explained how the control circuit according to the invention controls the electro magnetic coil 70 of the valves •• did so that aioh daa valve can open automatically, if within 250 milliseconds of the opening of the yen tiles no fropfdetektorsignal has been generated if only one such case occurs or a limited t or for any other temporary reason that does not require intervention Maohan · An andarea problem as is how the control system is automat! β oh rüokgestallt who «» can so that ea works properly when the next drop is actually received

First of all, let the system for resetting the tax *

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systems explained. Wtnn dtr transistor 228 includes, there is a sharp voltage drop across the atinta collector. Dit · is used as a signal for tintn fallen Tropfon Btnutstf that on tintn capacitor 274 in dta Dtttktorkrti · 154 is given for xu lower durohm flow · Dtr reception this signal · · rtranlaflt dtn capacitor 274 »« «int charge duroh« int diode 276 to the integrator «u, w« · duroh dtr integrator reset in dtr smooth manner If there is a drop signal through the capacitor 1 $ 0, it will arrive »apart from the fact that the condtne *» Gate 274 is twice as large as the capacitor 190 and accordingly the integrator drives twice and strongly.

When the integrator is turned off in this way, transistors 208, 222 and 232 turn off. Both ends The solenoid coil 70 of the valve then passes through the Resistor 240 reversed to zero voltage · Dtr From » valve control circuit 166 has returned to "tint noraold isolation position" if there "signal for tintn failed drops to the dtr potitiYtn Kitamt dt" capacitor "274 trsohtint, stuck tint diode 276 da "negatire end ditto" Kendeneators and recharges it via a capacitor 266 to »Dtr Condtntator 266 has around 25 aal grdftr al «dtr Ktndtntntattr 274 "" o that every time the drop fails, the capacitor 266 and the capacitor 274 receives a charge, dit tint Change dtr voltage 266 by «int step ron. 0.4 ToIt causes. The voltage at the capacitor 266 T «rursaoht but tintn StromrUokflui in the integrator duroh tintn Against "tan" 270 *

The "return charge that is given to the integrator by the capacitor 274 each time" has failed in the Trtpftn, originates from the capacitor 266 and becomes yen dta integrator over tint relatir reached Jeitepanne duroh j dtn Wideretand 270 surüok given. In this way, dit

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Total dtr charges at the integrator output and the constant flow rate kept at the "ing" divided value despite occasional drops Reset the integrator · Later, the capacitor 266 receives the resistor 270 a quantity of charge as an Irtate. Tuck added look below the of de * Integrator abflitSendea electricity and Yerarsaeht a leiohte Zuaaame the frequent of the drip duck can s · This increase takes txpontntitll, and is su after the eleventh time Vuil ₉ when iie borrowed amount of charge rüokerstattet 1st · Di "leiohte increase in Durehflufrate over the period of reimbursement compensates for the lost drops in an exact way and the average flow rate over a longer period corresponds to the set rate.

The capacitor 266 is also used as a storage element for normal actuation of the alarm circuit 160 for low durations, only after a certain gate view! Tem drops have fallen. The capacitor 266 acts as an accumulator for failed 'meeting because a "series τ · η ausgefalltntn drop a series τοη sehrittweisem changes its charge rerursacht · If the * β with resilient en Tropfon caused Ladungssohrltte fled on the leadensater 266 accumulate faster than the departure dor If the charge corresponds to the resistance 270, then the "span" rises to the capacitor 266. In the case of a lotrag, which corresponds to the accumulation τοη about 4 drops, the voltage becomes large enough to send a transistor 264 a "lusehaltcn" Dieter a signal to the alarm circuit 160 for sa lower Durohfluf, which in turn switches on an LED 38 (torsugswoise rtt) to alert "in" over-warning "p" r "" m sa ·

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" ⁵⁹ ""■ 222A926

Time switch for blooming benrenzuttj

A transistor 278 forms iuiuuin »it with IhB Yerbu * - the time stop network, consisting of the resistors 280 and 282 and one "capacitor 284," in time " krti · «ur limitation tintr DurohfluBfelookierung«

If the constant flow rate of the parenteral fluid fails has a certain minimum value, then all veins of the patient are not adequately flushed and in the quay clumping can arise · Um this su Yerhi & dern is the timer for limiting the blooming was seen, which sets a limit regarding the maximum time to swisohen two drops of the liquid · This limit is arbitrarily set to 1.5 minutes. The transistor 278 is usually included · Everyone's ad Drop causes capacitor 284 to be charged through diode 290 to -5.4 volts. Well, every drop of anxe the capacitor 284 is gradually discharged to zero through the resistors 280 and 282. The rate of discharge is like this chosen that if another drop chance does not occur within 2.5 minutes, the capacitor 284 on the Is discharged at which transistor 278 'loses its base drive signal and turns off Voltage across a voltage divider, consisting of the resistors 286, 267 and 268, against -6 volts. The transistor 264 in the detector circuit for low flow rates is then switched on by its emitter connection, which causes the alarm circuit 160 for too low flow Activity sets

If, as already explained, the liquid level in the container falls below a certain alarm value, then turned off by transistor 293 in amplifier 148 for the liquid level sensor, the wiper of the rate control potentiometer. This causes a fixation

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the flow rate to about 4 milliliters per hour · The current setting this rate is thru the transistor 273 and the resistor 268 at the OCW end of the potentiometer 198 provided, If the liquid flows continuously until the bottle is empty, then it will stop dripping from the container once, but continue to flow from the drip chamber 20 each time the valve is open · When the drop delivery fails are stopped shortly thereafter, then the liquid is completely emptied from the drip canoe and from the SoHMuohen 22 and 26 and air is introduced into the patient's tendons.

When the liquid in the bottle 14 is completely empty, the drop display also stops · Within 2.5 minutes transistor 278 is turned off and power to the integrator is terminated. Since the integrator cannot charge, He can also not switch on the valve control circuit 166 · Therefore, the entire flow of liquid is stopped, but the The supply in the drop chamber 20 is exhausted and no air is injected Duroh a person to monitor the liquid level again has been added «The device will automatically resume operation only if the conditions are given for normal operation "

Alarm circuits

The three alarm circuits 158, 160 and 162 are practically identical. In each alarm circuit, a Xippso oscillation oscillator responds to the current it receives from the associated one Detector receives, and immediately its associated Idohtemitterdiode starts with a relatively high current strength (80 mA) once every 2 seconds about 40 milliseconds

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* _λ ι ' ϋ

pulsate for a long time. This creates a series of brilliant red flashes on the front of the control unit 24 to indicate the source of the fault. To these most highly visible The alarm circuit only needs to generate signals xu an average battery current of 1.6 ml. Required quiescent current for the alarm circuit is zero

Since the alarms are the same, only the circle 158 is explained for xu low liquid level. Two transistors 294 and 296 are connected together in a positive feedback configuration. When the transistor 293 in the amplifier 148 for the fluid level sensor switches off, then current can flow through a resistor 306 and a capacitor 298 begins to charge negatively. When the positive terminal of capacitor 298 reaches about -1 volts, the base of transistor 294 conducts, obtaining current through the base-emitter path of a transistor 310 in alarm circuit 164. The collector of the transistor 294 then becomes conductive and switches the transistor 296 on via a resistor 308. The collector of transistor 296 then drops to 6 volts, driving LED 32, resistor 304, and diode 200. The resulting negative voltage drop across a resistor 302 is fed back via the capacitor 298 to the base of the transistor 294, which leads the transistor 294 very strongly into saturation. The LED 32 in series with the resistor 302 forms a voltage divider circuit that determines the anode voltage for the Diode 300 supplies -4 volts. Capacitor 298 continues to charge through resistor 304 and the base-emitter path of transistor 294. The charging current for ά · η capacitor reioht out, to keep the transistor 294 on extreme saturation. When the negative terminal of the capacitor 298 reaches -4.6 volts, the diode 300 becomes conductive and the current through the resistor 304 is diverted through the diode 300.

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tet so that he no longer through the capacitor 298 and the base-emitter path of transistor 294 flows. The weak current through resistor 306 is insufficient for the Keep transistor 294 in extreme saturation so that transistor 294 begins to lose saturation. The decrease in the basic drive signal at the Traneistor 296 causes a slight increase in its collector voltage. This slight increase becomes through the ItED 32 and the diode 300 and thus through the capacitor 298 of the base of the Transistor 294, where it has a further decrease in the B * · sis drive signal caused. Both transistors 294 uad 296 are shut down quickly. Capacitor 298 provides a positive x 4 volt step voltage to the base of transistor 294, turning that transistor off remain. Then the capacitance 298 charges through the resistor 306 again, whereby about 2 seconds elapse, until the switch-on value of transistor 294 is reached again, which then emits another 40 millisecond pulse * sseugt

The transistors 294 in each of the alarm circuits are connected connected to the other and draw power through the base-emitter path of transistor 310 in alarm circuit 164. If any of the alarms are triggered, transistor 310 switched on for 40 milliseconds · This acts on a Beiais 310, which closes its single contact 316 · The closing contact 316 completes a circle over signal lines 318 to a remote guard station 320 where the nurse receives the signal to aohten the patient "

The above description treats only an aspect exemplary embodiment of the invention and is not intended to limit its scope

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Claims (1)

Patent claims Durohflow regulator for an arrangement for supplying a parenteral liquid to a patient, characterized by a liquid control valve (5O) ₉ which, by continuously repeated actuation, allows the liquid to pass through in small portions, by means of a Vorriohtungteil that continuously forms drops from the liquid and by means of Hegel elements (62, 64,66,68,72,76), which set the number of actuations of the valve in the time unit (valve holding rate) as a function of the number of drops formed in the time unit (drop formation rate) 2 · Regulator according to Anepruoh 1, characterized in that the Valve hold rate is at least equal to the drop formation rate 3 · Regulator according to claim 1, characterized in that the Control elements for actuating the valve (50) as a function of a predetermined time delay the drop formation can be put out of action 4 · Regulator according to Claim 1, characterized in that the drop formation rate with a preset value is compared and that an alarm signal is generated if the drop formation rate differs by more than a predetermined value from the target value. 5 · Regulator according to Claim 4, characterized by a sensing device (30,148,158) for the level of the storage tank. gels of parenteral fluid, which generates an alarm signal when the fluid level drops below a specified value 20 988 2/06 00 6β regulator according to one of claims 1 to 5, characterized in that that the valve (50) is an electromagnetic shut-off valve whose valve body (56.97 »1O4) is at least consists partially of magnetic material, and that a magnetic device (70) is provided which a Magnetic field generated by which the valve body can be tilted and lifted from its seat Regulator according to Claim 6, characterized in that a valve housing (52) is provided which holds the valve body (56.97t104) and the valve seat (54) and which forms a stop next to the valve seat to limit the lateral movement of the valve body, when this is lifted from the valve seat, and to hold the valve body in its outermost lifted position Position in which the flow of liquid through the valve tends to push the valve body against its seat to press 8 · Regulator according to claim 7, characterized in that the magnetic device (70) which lift off the valve body can generate a lateral magnetic force that tilts the valve body against the valve housing and the valve opens. Regulator naoh claims 1 to 8 for intravenous pouring of liquids, characterized in that the Vorriohtungteil for the drop formation and the control valve (50) are part of a closed line leading to the patient, in which there is also a droplet chamber (20) which catches the droplets as they fall, and that the opening and closing of the valve (50) takes place as a function of the droplet formation " 10. Regulator naoh Anspruoh 9, characterized in that 209882/0600 2224929 the length of time the valve (50) is open during the formation of each drop is a direct function of the length of time between successive drops ο 11. Regulator according to Anspruoh 9 _t, characterized in that the valve (50) is quickly transferred from the fully open to the fully closed state. 12o controller naoh one of claims 9 to 11, characterized in that the devices for controlling the opening and closing the valve an oscillator (68), as well as means (66) to adjust its frequency as a function of the drop size. 13 · Regulator naoh Claim 6 or one of the following claims, characterized by the fact that the valve body (56,97) from a base part serving as a plate to rest on the transversely extending valve seat (54) (60,92,102) and consists of a longitudinally extending rod (58.88.98) which is at least partially made of magnetic material 14 · Regulator according to Claim 6 or one of the following, characterized in that the magnetic device, the that generates the field tilting the valve body, is an electromagnet (70), and that holding devices (62, 64,66,68) are provided in order to apply electrical energy to this electromagnet intermittently » 15 · Regulator according to Claim 14, characterized by the fact that the means for acting on the electromagnet (70) can be actuated as a function of the drop formation are· 209882/0600 16. Regulator according to claim 13, characterized in that the base portion (60,92,102) of the valve body (56) is wider than the distal end of the rod (53,88,98), 17 · Hegler according to claim 16, characterized in that the rod (88) extends upstream from the valve seat (Figs. 3 and 4) 18. Regulator according to claim 16, characterized in that the rod (98) extends downstream from the valve seat (Mg.5). 19 · Magnetic valve, in particular for a flow regulator according to one of Claims 1 to 18, characterized by a part which forms a valve seat (54),
duroh a movable valve body (56,97), which rests with its base part (60,92,102) on the valve seat and has a rod (58, 88,98) which protrudes outward from the base part and which consists at least partially of magnetic material, and through a magnetic device (70) that generates a magnetic force that
the valve body (56,97) tilts from its seat and thus the valve opens. 20 valve according to claim 19, characterized in that the valve seat (54) is at right angles to the direction of flow
extends through the valve and that the valve body
(56.97) around an edge of its base (60,92,102)
eohwoves when it is tilted 21. Valve according to claim 19, characterized in that the rod (58.88) against the flow direction through the valve has _β 209882/0600 22 · Valve according to claim 19, characterized in that the rod (98) in the direction of flow through the valve points o 23. Valve according to claim 21, characterized in that the valve body (56) in its exterior substantially is conical in shape 24. Valve according to claim 19, characterized in that the magnetic device has a force component acting laterally on the rod (58.88.98) of the valve body (56.97) generated· 25ο valve according to claim 19 with a valve housing, characterized characterized in that the magnetic device (70) is arranged laterally outside the housing (52) 26. Valve according to claim 25, characterized in that the magnetic device is an electromagnet (70) and that means (68) are provided for this electromagnet to be charged periodically, 27 · Magnetic valve, in particular for a thermosetting flow regulator according to one of Claims 1 to 18, characterized by a housing (52) which has a valve seat (93) is formed by a movable magnetic valve body (104) which is shaped to fit onto the valve seat fits and the valve closes, duroh a stop next to the valve body and the valve seat to limit the lateral movement of the valve body from its seat and for holding the valve body in its Located at the extreme point of its lateral movement, where the flow through the valve seeks the valve body to press on his seat, as well as finally borrowed by a magnetic device (70), which is a 209882/0600 generated lent acting magnetic force that urges the valve body (104) away from the valve seat against the lateral stop, and thereby open the valve (Fig 6 _E) · 28 · Valve according to claim 27, characterized in that the valve body (104) is spherically shaped 29 Valve according to Anepruoh 27 * characterized in that one normally above the valve body Float (105) is provided which presses the valve body (104) naoh up on its site when the valve is turned upside down 50o magnetic · valve, in particular for a Durohm flow regulator according to one of claims 1 to 18, characterized through a valve housing (52) instead of a valve arranged in it transversely to the direction of flow of the liquid * seat (54), through a valve body (56,97) with a laterally extending base part (92), which as Abutment on the valve seat is used, and a rod (88,98) which extends in the longitudinal direction through the valve housing, the rod being narrower than the Has a base part and a part made of magnetic material, and by means of a Magnetetrorriohtung (70) outside the valve housing, a laterally acting magnetic Able to exert force on the rod of the valve body in order to tilt it sideways and thereby open the valve » 31 · Valve naoh Anepruoh 30, characterized in that the valve body (56) is essentially conical in shape and the rod (88) extends upstream from the valve seat * extends downwards (Figo 3 and 4) 32. Valve according to claim 30, characterized in that the rod (98) moves downstream from the valve seat 209882/0600 ~ ⁴⁹ ~ 2224928 streokt (Pig · 5). 33. Valve naoh Anspruoh 30, characterized, äaß the magnetic device consists of an electromagnet (70) consists. with device parts' (62,64,66,68), which the Periodically supply the electromagnet with power © 34. Regulator naoh claim 1, characterized by a Drop detector (76) to determine the drop fall and aur determination of the amount of liquid flowing to the patient per unit of time (Durohflußrate) in the Relationship to the drop formation rate, as well as by means (166) which automatically close the valve when the period of time between droplets formed on one another exceeds a specified value 33 · Regulator according to Claim 34, characterized in that every time an automatic closing of the Ven · » If the time between successive drop formations is too long, a signal is generated that these signals accumulate over a certain period of time and gradually enter the control system be introduced to compensate for the flow rate drop and maintain a steady flow rate keep· 36. Regulator naoh Anspruoh 34 or 35, characterized in that the drop detector (76) has a first electrode (137) which comes into contact with the liquid upstream of the point where the drop is formed, and a second electrode (140) which slightly lies below the point of drop formation, so that it only comes into contact with the drop when this begins to take off at its underside in the Suroh knife in order to detach itself from the liquid lying above it, but before it is completely removed from the 209 882/060 0 has separated the remaining liquid. 37. Controller i: sh one of claims 1 to 18 and 34 to
36, daduroh marked! that in each case a certain minimum continuous flow rate is obtained by providing means to automatically turn the valve
Press EU if no drop formation can be detected for a certain period of time 209882/0600 Blank page